Apparatus for infusing fluid
A pump for pumping fluid includes a tube platen, a plunger, a bias member, inlet and outlet valves, an actuator mechanism, a position sensor, and a processor. The plunger is configured for actuation toward and away from the infusion-tube when the tube platen is disposed opposite to the plunger. The tube platen can hold an intravenous infusion tube. The bias member is configured to urge the plunger toward the tube platen.
1. A pump for pumping fluid, the pump comprising:
a tube platen;
a plunger configured for actuation toward and away from the tube platen when the tube platen is disposed opposite to the plunger;
a bias member configured to urge the plunger toward the tube platen;
an inlet valve upstream of the plunger configured for actuation between an occluding position and a non-occluding position;
an outlet valve downstream of the plunger configured for actuation between an occluding position and a non-occluding position;
an actuator mechanism configured to control the actuation of the plunger, the inlet valve and the outlet valve, wherein the actuator mechanism is configured to mechanically engage and disengage from the plunger to pump fluid toward a patient, wherein when the actuator mechanism is disengaged from the plunger, the actuator mechanism is configured to mechanically discharge the bias member such that the bias member acting upon the plunger is a sole force driving the plunger toward the tube platen, wherein the actuator mechanism is configured to engage the plunger to lift the plunger away from the tube platen to thereby mechanically charge the bias member, wherein the actuator mechanism comprises a cam shaft and a plunger cam coupled to the cam shaft configured to actuate the plunger;
a pressure sensor disposed adjacent to at least one of the inlet valve, the outlet valve, and the plunger;
a position sensor configured to estimate a position of the plunger; and
a processor coupled to the position sensor to receive the estimated position of the plunger therefrom, wherein the processor is configured to detect an anomaly based in part on the estimated plunger position when:
the inlet valve is in the occluding position,
the outlet valve is in the occluding position,
the actuator mechanism is mechanically disengaged from the plunger thereby making the bias member the sole source of actuation force of the plunger toward the tube platen, wherein the plunger cam is not in contact with a plunger-cam follower of the plunger when the plunger position is estimated; and
the bias member urges the plunger toward the tube platen,
wherein the processor is further coupled to the pressure sensor to receive a pressure signal from the pressure sensor, the processor is configured to, using the pressure signal, to determine a downstream occlusion exists if a subtraction of a filtered value of a sequential series of sequential trough-to-trough pressure values of a plurality of cycles from a trough-to-trough value is greater than a predetermined threshold.
2. The pump according to claim 1 , wherein the processor is configured to detect a leak based on a rate of change of the estimated position of the plunger.
3. The pump according to claim 1 , the pump further comprising an ultrasonic sensor sensitive to gas in an infusion tube, the ultrasonic sensor located downstream of the plunger and configured communicate with the processor, wherein the processor is configured to distinguish between an upstream occlusion and a presence of air in the fluid using the ultrasonic sensor.
4. The pump according to claim 1 , the pump further comprising an ultrasonic sensor sensitive to gas in an infusion tube, the ultrasonic sensor located downstream of the plunger and configured communicate with the processor, wherein the processor is configured to determine a volume of air pumped downstream based on the plunger position when both the inlet and outlet valves occlude the infusion tube and on the sensed gas.
5. The pump according to claim 1 , wherein the tube platen is configured to hold an intravenous infusion tube.
6. The pump according to claim 1 , further comprising:
a housing; and
a door pivotally coupled to the housing, the door configured to pivot to an open position and to a closed position, wherein the tube platen is disposed on the door.
7. The pump according to claim 6 , wherein the tube platen, the door, and the plunger are configured such that the plunger is configured for actuation toward and away from the infusion-tube when the door is in the closed position.
8. The pump according to claim 7 , further comprising:
a lever pivotally coupled to the door, the lever having first and second positions; and
a latch coupled to the door, wherein the lever is configured to latch the door onto the housing when in the first position.
9. The pump according to claim 8 , wherein the first position is defined as a position in which the lever is pivoted toward to the door.
10. The pump according to claim 8 , further comprising a carrier having first and second portions pivotally coupled together, wherein:
the door and the carrier co-pivot together,
the housing includes a first slot in which the first portion of the carrier is at least partially disposed when the door is in the open position,
the door includes a second slot in which the second portion of the carrier is disposed within when the door is in the open position, and
the lever is operatively coupled to the second portion of the carrier such that when the door is in the closed position, lever actuation toward the first position pushes the first and second portions of the carrier into the first slot of the housing.
11. The pump according to claim 1 , wherein the plunger cam is configured to lift the plunger away from the tube platen.
12. The pump according to claim 1 , wherein the processor detects the anomaly when only a force of the bias member forces the plunger toward the tube platen.
13. The pump according to claim 1 , wherein the processor detects the anomaly when only a force of the bias member forces the plunger toward the tube platen.
14. The pump according to claim 1 , wherein the processor is configured to communicate data to a monitoring client.
15. The pump according to claim 14 , wherein the data includes an indication of the anomaly.
16. A pump for pumping fluid, the pump comprising:
a tube platen;
a plunger configured for actuation toward and away from the tube platen when the tube platen is disposed opposite to the plunger;
a bias member configured to urge the plunger toward the tube platen;
an inlet valve upstream of the plunger configured for actuation between an occluding position and a non-occluding position;
an outlet valve downstream of the plunger configured for actuation between an occluding position and a non-occluding position;
an actuator mechanism configured to control the actuation of the plunger, the inlet valve and the outlet valve, wherein the actuator mechanism comprises a cam shaft and a plunger cam coupled to the cam shaft configured to actuate the plunger, wherein:
the actuator mechanism is configured to mechanically engage and disengage from the plunger to pump fluid toward a patient,
when the actuator mechanism is disengaged from the plunger, the actuator mechanism is configured to mechanically discharge the bias member such that the bias member acting upon the plunger is a sole force driving the plunger toward the tube platen, and
the actuator mechanism is configured to engage the plunger to lift the plunger away from the tube platen to thereby mechanically charge the bias member;
a pressure sensor disposed adjacent to at least one of the inlet valve, the outlet valve, and the plunger;
a position sensor to estimate the position of the plunger; and
a processor coupled to the position sensor and configured to estimate fluid flow in accordance with the estimated position of the plunger when the inlet and outlet valves are closed and the plunger cam is not in contact with a plunger-cam follower of the plunger, the processor is further coupled to the pressure sensor to receive a pressure signal from the pressure sensor, wherein:
the inlet valve, the outlet valve, and the plunger are configured to pump fluid in a plurality of cycles, each cycle having a trough pressure level and a peak pressure level, and
the processor is configured to, using the pressure signal, to determine a downstream occlusion exists if a subtraction of a filtered value of a sequential series of sequential trough-to-trough pressure values of the plurality of cycles from a trough-to-trough value is greater than a predetermined threshold.
17. The pump according to claim 16 , wherein the pressure signal is filtered prior to being received by the processor.
18. The pump according to claim 16 , further comprising an analog filter configured to filter the pressure signal prior to being received by the processor.
19. The pump according to claim 16 , wherein the processor is configured to communicate data to a monitoring client.